94 B350: HVAC Questions
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From: Baltimore County
94 B350: HVAC Questions
My primary issues are
1. The Heat position on the switch directs air out of the Defrost/windscreen vents, not the dash vents. All other positions operate as intended.
2. With the temp selection all the way to the right/Heat, ambiant temperature air is blowing out the Heat/Defrost vents (i.e. - it aint heating up). This is with the engine temp up (I guess 190 or so). When I was fiddling with this, it was a pretty warm night.Until it cools down and can test again in cooler temps, I'm not convinced this is an issue. It blew very hot in the spring and was just testing it out after overhauling hte cooling systm including replacing some heater hoses.
I know I need to do some more investigating/researching regarding blend door linkages, vacuum lines, etc but I'm trying to get an understanding on how the whole thing operates.
This is my understanding...please let me know if I'm incorrect.
- The a/c compressor runs regardless of temp selection.
- The a/c compressor runs regardless of vent position selection. I've come across a post that indicates the compressor won't run in select positions(presumably when norm or bi-level 'pull' selections are made).
What actions will 'actuate' (apply vaccum to) the heat control valve (i.e. - how do I test this is operating properly)?
Judging by the hot temps of the hoses on either side, the position in the picture is the open/flow position. No matter what temp/vent selections I
make, it seems to just stay in this position. I played with the temp/vent selections a bit and was unable to get any detectable vaccum out the line feeding the valve itself.
1. The Heat position on the switch directs air out of the Defrost/windscreen vents, not the dash vents. All other positions operate as intended.
2. With the temp selection all the way to the right/Heat, ambiant temperature air is blowing out the Heat/Defrost vents (i.e. - it aint heating up). This is with the engine temp up (I guess 190 or so). When I was fiddling with this, it was a pretty warm night.Until it cools down and can test again in cooler temps, I'm not convinced this is an issue. It blew very hot in the spring and was just testing it out after overhauling hte cooling systm including replacing some heater hoses.
I know I need to do some more investigating/researching regarding blend door linkages, vacuum lines, etc but I'm trying to get an understanding on how the whole thing operates.
This is my understanding...please let me know if I'm incorrect.
- The a/c compressor runs regardless of temp selection.
- The a/c compressor runs regardless of vent position selection. I've come across a post that indicates the compressor won't run in select positions(presumably when norm or bi-level 'pull' selections are made).
What actions will 'actuate' (apply vaccum to) the heat control valve (i.e. - how do I test this is operating properly)?
Judging by the hot temps of the hoses on either side, the position in the picture is the open/flow position. No matter what temp/vent selections I
make, it seems to just stay in this position. I played with the temp/vent selections a bit and was unable to get any detectable vaccum out the line feeding the valve itself.
Last edited by daguvena88; Sep 10, 2013 at 02:31 PM.
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Joined: May 2008
Posts: 1,174
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From: North TX
Both hoses may have been warm/hot just from being in the enclosed envoirment of our engine compartments. Also to add to what Blackvan said I would back flush the core out. Disconnect the hoses from the core and using a four foot length of new hearter hose connect to one side of the core and flush with your garden hose water, then connecto the other port and flush the core out the other way, this makes sure all the crude gets removed. If you cannot get a a good flow out of the core then it may have to be replaced.
On these vans (1997 and older) the AC compressor will not run accept in the AC Max, AC, Bi-Lev, and Defrost position.
On these vans (1997 and older) the AC compressor will not run accept in the AC Max, AC, Bi-Lev, and Defrost position.